Abstract
When 6,7-dimethyl-2,3-dioxotetrahydroquinoxaline (oxoviolet) and 4,6,7-trimethyl-2,3-dioxotetrahydroquinoxaline was treated with dimethyl sulfate in alkaline solution, the same methylated compound was obtained which was proved to be 1,4,6,7-tetramethyl-2,3-dioxotetrahydroquinoxaline (methyloxoviolet). When 6,7-dimethyl-4-D-ribityl-2,3-dioxotetrahydroquinoxaline (flavoviolet)was treated with dimethylsulfate in alkaline solution, 1,6,7-trimethyl-4-D-ribityl-2,3-dioxotetrahydroquinoxaline was formed which yielded methyloxoviolet by treating with hydrogen peroxide in a hot alkaline solution.
